CATH Classification
| Level | CATH Code | Description |
|---|---|---|
|
3 | Alpha Beta |
|
3.90 | Alpha-Beta Complex |
|
3.90.70 | Cathepsin B; Chain A |
|
3.90.70.150 | Helper component proteinase |
Domain Context
CATH Clusters
| Superfamily | Helper component proteinase |
| Functional Family |
Enzyme Information
| 3.4.22.44 |
Nuclear-inclusion-a endopeptidase.
based on mapping to UniProt P89509
Hydrolyzes glutaminyl bonds, and activity is further restricted by preferences for the amino acids in P6 - P1' that vary with the species of potyvirus, e.g. Glu-Xaa-Xaa-Tyr-Xaa-Gln-|-(Ser or Gly) for the enzyme from tobacco etch virus. The natural substrate is the viral polyprotein, but other proteins and oligopeptides containing the appropriate consensus sequence are also cleaved.
-!- The potyviruses cause diseases in plants, and inclusion bodies appear in the host cell nuclei, protein a of these being the endopeptidase. -!- The enzyme finds practical use when encoded in vectors for the artificial expression of recombinant fusion proteins, since it can confer on them the capacity for autolytic cleavage. -!- It is also reported that transgenic plants expressing the enzyme are resistant to viral infection. -!- Belongs to peptidase family C4.
|
| 3.4.22.45 |
Helper-component proteinase.
based on mapping to UniProt P89509
Hydrolyzes a Gly-|-Gly bond at its own C-terminus, commonly in the sequence -Tyr-Xaa-Val-Gly-|-Gly, in the processing of the potyviral polyprotein.
-!- Known from many potyviruses. -!- The helper component-proteinase of the tobacco etch virus is a multifunctional protein with several known activities. -!- The N-terminal region is required for aphid transmission and efficient genome amplification, the central region is required for long-distance movement in plants, and the C-terminal domain has cysteine endopeptidase activity. -!- Belongs to peptidase family C6.
|
| 2.7.7.48 |
RNA-directed RNA polymerase.
based on mapping to UniProt P89509
Nucleoside triphosphate + RNA(n) = diphosphate + RNA(n+1).
-!- Catalyzes RNA-template-directed extension of the 3'-end of an RNA strand by one nucleotide at a time. -!- Can initiate a chain de novo. -!- See also EC 2.7.7.6.
|
| 3.6.4.- |
Acting on ATP; involved in cellular and subcellular movement.
based on mapping to UniProt P89509
|
| 3.4.-.- |
Acting on peptide bonds (peptidases).
based on mapping to UniProt P89509
|
UniProtKB Entries (1)
| P89509 |
POLG_TUMVJ
Turnip mosaic virus
Genome polyprotein
|
PDB Structure
| PDB | 3RNV |
| External Links | |
| Method | X-RAY DIFFRACTION |
| Organism | |
| Primary Citation |
Structure of the autocatalytic cysteine protease domain of potyvirus helper-component proteinase
to be published
|
